The present invention relates to (a) novel fluorine-containing monomers having a special structure, that is, a hydroxyl group or a substituent for protecting or modifying hydroxyl group, (b) polymers prepared by polymerization or copolymerization of such monomers, and (c) materials (e.g., reflection preventive materials, photosensitive coatings, and resist materials) containing such polymers.
Fluorine-containing compounds have been used and developed in various fields particularly in the field of advanced materials due to their good qualities (e.g., water repellency, oil repellency, low water absorption, heat resistance, weather resistance, corrosion resistance, transparency, photosensitivity, low refractive index, and low dielectric property). In particular, there have been active researches and developments of fluorine-containing compounds in the fields of (a) reflection preventive films utilizing low refractive index and visible light transparency of fluorine-containing compounds, (b) optical devices utilizing transparency of fluorine-containing compounds in a long wavelength band for optical communication, and (c) resist materials utilizing transparency of fluorine-containing compounds in ultraviolet region (particularly vacuum ultraviolet wavelength region). In these fields, the common task of designing polymers is to achieve adhesion to the substrate and high glass transition point (hardness), while achieving transparency at each wavelength for use by introducing as many fluorine atoms as possible into the polymer. Although there have been various proposals for increasing transparency at each wavelength by increasing the fluorine content in the polymer, there is no or very few proposals for improving water repellency and adhesion and for obtaining higher glass transition point by newly designing fluorine-containing monomers themselves. Recently, there have been some reports of hydroxyl group-containing and fluorine-containing styrenes and hydroxyl group-containing and fluorine-containing norbornene compounds in the field of the next generation F2 resist in vacuum ultraviolet region. However, there are demands for new materials (i.e., novel polymers and novel monomers for providing novel polymers) having a sufficiently low refractive index necessary for reflection preventive films, for those having a sufficient transparency at optical communication wavelength, and for those having both of a sufficient transparency in ultraviolet region and a sufficient etching resistance.